From cff3ccd11d9ed09e01ce0b63455ed51e3147cecf Mon Sep 17 00:00:00 2001
From: Natalia Portillo <claunia@claunia.com>
Date: Mon, 11 Feb 2019 01:42:50 +0000
Subject: [PATCH] Add OutputByteInputTableCodingLoop class.

---
 .../Claunia.ReedSolomon.csproj                |  1 +
 .../OutputByteInputTableCodingLoop.cs         | 38 +++++++++++++++++++
 2 files changed, 39 insertions(+)
 create mode 100644 Claunia.ReedSolomon/OutputByteInputTableCodingLoop.cs

diff --git a/Claunia.ReedSolomon/Claunia.ReedSolomon.csproj b/Claunia.ReedSolomon/Claunia.ReedSolomon.csproj
index eddcc6b..ac934e8 100644
--- a/Claunia.ReedSolomon/Claunia.ReedSolomon.csproj
+++ b/Claunia.ReedSolomon/Claunia.ReedSolomon.csproj
@@ -51,6 +51,7 @@
         <Compile Include="InputOutputByteTableCodingLoop.cs" />
         <Compile Include="Matrix.cs" />
         <Compile Include="OutputByteInputExpCodingLoop.cs" />
+        <Compile Include="OutputByteInputTableCodingLoop.cs" />
         <Compile Include="Properties\AssemblyInfo.cs" />
     </ItemGroup>
     <ItemGroup>
diff --git a/Claunia.ReedSolomon/OutputByteInputTableCodingLoop.cs b/Claunia.ReedSolomon/OutputByteInputTableCodingLoop.cs
new file mode 100644
index 0000000..7093500
--- /dev/null
+++ b/Claunia.ReedSolomon/OutputByteInputTableCodingLoop.cs
@@ -0,0 +1,38 @@
+/**
+ * One specific ordering/nesting of the coding loops.
+ *
+ * Copyright 2015, Backblaze, Inc.  All rights reserved.
+ * Copyright © 2019 Natalia Portillo
+ */
+
+namespace Claunia.ReedSolomon
+{
+    public class OutputByteInputTableCodingLoop : CodingLoopBase
+    {
+        public override void CodeSomeShards(byte[][] matrixRows, byte[][] inputs, int inputCount, byte[][] outputs,
+                                            int outputCount, int offset, int byteCount)
+        {
+            byte[][] table = Galois.MULTIPLICATION_TABLE;
+
+            for(int iOutput = 0; iOutput < outputCount; iOutput++)
+            {
+                byte[] outputShard = outputs[iOutput];
+                byte[] matrixRow   = matrixRows[iOutput];
+
+                for(int iByte = offset; iByte < offset + byteCount; iByte++)
+                {
+                    int value = 0;
+
+                    for(int iInput = 0; iInput < inputCount; iInput++)
+                    {
+                        byte[] inputShard   = inputs[iInput];
+                        byte[] multTableRow = table[matrixRow[iInput] & 0xFF];
+                        value ^= multTableRow[inputShard[iByte] & 0xFF];
+                    }
+
+                    outputShard[iByte] = (byte)value;
+                }
+            }
+        }
+    }
+}
\ No newline at end of file